Surgical fastener applying apparatus

ABSTRACT

The present disclosure relates to a surgical fastener applying apparatus ( 10 ) for sequentially applying fasteners to body tissue. The apparatus includes a clamping half-section ( 12 ) having a distal anvil attachment portion ( 12   b ) and a proximal handle portion ( 12   a ), a cartridge receiving half-section ( 14 ) having a handle portion ( 22 ) and an elongated channel portion ( 24 ), the elongated channel portion being configured to releasably receive a single use loading unit and the handle portion being configured to releasably receive a firing assembly ( 20 ), an anvil member ( 16 ) configured to be releasably supported within the distal anvil attachment portion of the clamping half-section and a firing assembly configured to be releasably supported within the handle portion of the cartridge receiving half-section.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application of PCT/US13/68253 under 35USC § 371 (a), the disclosure of the above-identified application is hereby incorporated by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a surgical fastener applying apparatus and, more particularly, to a surgical fastener applying apparatus having reusable and disposable components.

2. Discussion of Related Art

Surgical fastener applying apparatus, wherein tissue is first grasped and clamped between opposing jaw structures and then joined by means of surgical fasteners, are well known in the art. In some such apparatus, a knife is provided to cut the tissue which has been joined by the fasteners. The fasteners are typically in the form of surgical staples, although, other surgical fasteners may also be utilized, such as, for example, clips or two part polymeric surgical fasteners.

Surgical fastener applying apparatus typically include two elongated beam members which are used to capture or clamp tissue therebetween. Typically, one of the beam members carries a disposable cartridge assembly which houses a plurality of staples arranged in at least two lateral rows, while the other beam member includes an anvil which defines a surface for forming the staple legs as the staples are driven from the cartridge assembly. Where two part fasteners are used, the beam member which includes the anvil carries a mating part of the two part fastener, e.g. the receiver.

Generally, the staple formation process is affected by the interaction between one or more longitudinally moving camming members and a series of individual staple pushers. As the camming members travel longitudinally through the cartridge carrying beam member, the individual pusher members are biased upwardly into a backspan of the staples supported within the cartridge assembly to sequentially eject the staples from the cartridge. A knife may be provided to travel with the camming members between the staple rows to cut the tissue between the rows of formed staples. An example of such an instrument is disclosed in U.S. Pat. No. 7,631,794, which is incorporated herein in its entirety by reference.

Because of the dangers associated with improper sterilization, surgical fastener applying apparatus are typically disposable after use. Although the cartridge assembly may be replaced during a surgical procedure to perform multiple fastener applying operations on a single patient, the staple applying apparatus is typically disposable after a surgical procedure has been completed and is not used on different patients. This requirement of disposability may increase the costs associated with surgical procedures. Although reusable fastener applying apparatus have been developed, such apparatus can be overly complex and prove difficult to sterilize.

A need exists in the art for a fastener applying apparatus which includes reusable components, is not overly complex and is configured to facilitate proper sterilization after use in a surgical procedure.

SUMMARY

The present disclosure relates to a surgical fastener applying apparatus for sequentially applying fasteners to body tissue. The apparatus includes a clamping half-section having a distal anvil attachment portion and a proximal handle portion, a cartridge receiving half-section having a handle portion and an elongated channel portion, the elongated channel portion being configured to releasably receive a single use loading unit and the handle portion being configured to releasably receive a firing assembly, an anvil member configured to be releasably supported within the distal anvil attachment portion of the clamping half-section and a firing assembly configured to be releasably supported within the handle portion of the cartridge receiving half-section.

In an embodiment, the firing assembly may include a stationary housing, a firing lever and a cam bar secured to the firing lever. The anvil member may be disposable independently of the clamping half-section and the clamping half section is reusable. The stationary housing may include a U-shaped frame having a bottom wall and a pair of sidewalls. Each of the sidewalls may have a proximal end defining detents which are configured to extend through the openings in a proximal end of the cartridge receiving half-section to releasably retain the stationary housing within the handle portion. The firing assembly may further include a knife actuating bar which is configured to engage a knife supported within the single use loading unit. The firing assembly may further include a guide block axially fixed within the U-shaped frame and a slide block slidably positioned with the U-shaped frame. The firing lever may be pivotally secured to the slide block and the cam bar may be fixedly secured to the slide block. The slide block may be slidable through the U-shaped frame to advance the cam bar through the distal portion of the elongated channel member.

In some embodiments, the cartridge receiving half-section includes a support member on proximal end thereof defining a vertical slot and the clamping half-section includes a protrusion on a proximal end thereof configured to releasably engage the support member. The anvil attachment portion may include a pair of cylindrical posts configured to releasably engage a proximal portion of the anvil member. The anvil member may include a pair of slots. The pair of slots may be configured to receive the pair of cylindrical posts. The pair of slots may have open ends which face in different directions. The anvil attachment portion may include two pairs of semi-arcuate slots each configured to selectively receive a pair of lateral support members formed on the cartridge receiving half-section. The handle portion of each of the clamping half-section and the cartridge receiving half-section may be perforated. The handle portion of each of the clamping half-section and the cartridge receiving half-section may include a gripping portion. The handle portion of each of the clamping half-section and the cartridge receiving half-section may include a thumb engaging abutment. The surgical fastener applying apparatus may further include a single use loading unit configured to be releasably received within the elongated channel portion of the cartridge receiving half-section.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed surgical fastener applying apparatus will now be described herein with reference to the accompanying figures wherein:

FIG. 1 is a perspective view of an embodiment of the presently disclosed surgical fastener applying apparatus in the clamped position;

FIG. 2 is a perspective view with parts separated of the surgical fastener applying apparatus shown in FIG. 1;

FIG. 3 is a perspective view of the clamping half-section of the surgical fastener applying apparatus shown in FIG. 1;

FIG. 4 is a perspective view of the cartridge receiving half-section of the surgical fastener applying apparatus shown in FIG. 1;

FIG. 5 is a perspective view of the anvil member of the surgical fastener applying apparatus shown in FIG. 1;

FIG. 6 is a perspective view of the SULU and the firing assembly of the surgical fastener applying apparatus shown in FIG. 1;

FIG. 7 is a front end perspective view from above the firing assembly shown in FIG. 6;

FIG. 8 is an enlarged view of the indicated area of detail shown in FIG. 7;

FIG. 9 is a rear end perspective view from above of the firing assembly shown in FIG. 7;

FIG. 10 is an enlarged view of the indicated area of detail shown in FIG. 9;

FIG. 11 is a side perspective view of the firing assembly shown in FIG. 9 with parts separated;

FIG. 11A is a bottom perspective view of the cam bar of the firing assembly shown in FIG. 11;

FIG. 11B is a bottom perspective view of the firing lever of the firing assembly shown in FIG. 11;

FIG. 12 is a side perspective view of the SULU of the surgical fastener applying apparatus shown in FIG. 1;

FIG. 13 is an enlarged view of the indicated area of detail shown in FIG. 12;

FIG. 14 is a front perspective view of the SULU shown in FIG. 12;

FIG. 15 is an enlarged view of the indicated area of detail shown in FIG. 14; and

FIG. 16 is a side perspective view with parts separated of the SULU shown in FIG. 14.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed surgical fastener applying apparatus in accordance with the present disclosure will now be described in detail with reference to the drawings wherein like reference numerals identify similar or identical structural elements in each of the several views. As used herein, as is traditional, the term “proximal” refers to the end of the apparatus which is closer to the user and the term distal refers to the end of the apparatus which is further away from the user.

FIGS. 1-16 illustrate one embodiment of the presently disclosed surgical fastener applying apparatus designated generally as surgical stapler 10. Referring specifically to FIGS. 1 and 2, surgical stapler 10 includes a clamping half-section 12, a cartridge receiving half-section 14, an anvil member 16, a single use loading unit 18 (hereinafter “SULU”) and a firing assembly 20. In one embodiment, clamping half-section 12, cartridge receiving half-section 14 and anvil member 16 are constructed to be reusable components and, as such, are constructed from a biocompatible material suitable for sterilization and repeated use, e.g., stainless steel. In contrast, SULU 18 and firing assembly 20 are constructed to be disposable and, as such, may be constructed from any suitable biocompatible material, e.g., plastics, metals, combinations thereof, having the requisite strength characteristics. In some embodiments, anvil member 16 is constructed to be disposable.

With reference to FIGS. 1-3, clamping half-section 12 includes a proximal handle portion 12 a and a distal anvil attachment portion 12 b. Handle portion 12 a is ergonomically formed and includes a gripping portion 180 and a thumb engaging abutment 182. Handle portion 12 a is perforated for ease of cleaning and/or to reduce the weight of surgical stapler 10. A proximal end of handle portion 12 a includes a downwardly extending protrusion 186. Protrusion 186 may have a substantially circular cross-section, although other configurations are envisioned. Distal anvil attachment portion 12 b defines a recess 13 configured to receive a proximal end of anvil member 16. A pair of cylindrical posts 218 a, 218 b extends across recess 13. Each post 218 a, 218 b is positioned to engage an attachment section 196 of anvil member 16. Attachment section 196 is formed on a proximal end of anvil member 16 and will be discussed in further detail below. Anvil attachment portion 12 b is further configured to engage a mid-portion of cartridge receiving half-section 14 to effect movement of surgical stapler 10 to the clamped position (FIG. 1). Specifically, and as will be discussed in further detail below, anvil attachment portion 12 b includes first and second pairs of semi-arcuate slots 172 a and 172 b configured to receive lateral support members 194 a and 194 b, respectively, which are formed on cartridge receiving half-section 14.

With reference also to FIG. 5, anvil member 16 includes proximally located attachment section 196 and a staple deforming section 198 positioned distally of attachment section 196. Attachment section 196 is configured to be received within recess 13 of anvil attachment portion 12 b of clamping half-section 12 and defines a first slot 197 a configured to receive cylindrical post 218 a of anvil attachment portion 12 b and a second slot 197 b opposite of and longitudinally spaced from first slot 197 a configured to operably receive cylindrical post 218 b of anvil attachment portion 12 b. Assembly of anvil member 16 to clamping half-section 12 can be accomplished by inserting attachment section 196 of anvil member 16 within recess 13 of anvil attachment portion 12 b such that first cylindrical post 218 a of anvil attachment portion 12 b is received within first slot 197 a of attachment section 196. Once first cylindrical post 218 a is received within first slot 197 a, anvil member 16 is pivoted downwardly in a distal direction to position second cylindrical post 218 b within second slot 197 b. The positioning of posts 218 a, 218 b within slots 197 a, 197 b of attachment portion 196 secures anvil member 16 in relation to clamping half-section 12 and with respect to the cartridge receiving half-section 14 when surgical stapler 10 is in the clamped position (FIG. 1) to control the tissue gap between anvil member 16 and SULU 18.

With reference still to FIG. 5, staple deforming section 198 of anvil member 16, as known in the art, includes a plurality of staple deforming recesses and faces a top surface of SULU 18 when SULU 18 is attached to cartridge receiving half-section 14. As is also known in the art, staple deforming section 198 includes a central longitudinal slot (not shown) for receiving a knife 40 (FIG. 16) of SULU 18 as knife 40 is moved through SULU 18. Staple deforming section 198 may be formed integrally with anvil attachment portion 196, or in the alternative, secured to anvil attachment portion 196 by a fastening process such as welding. A pair of locating fingers 170 are positioned adjacent the proximal end of staple deforming portion 198 of anvil member 16. Locating fingers 170 are received in grooves in SULU 18 to properly align SULU 18 with staple deforming section 198 of anvil member 16 when surgical stapler 10 is in a clamped position. In addition, locating fingers 170 function to define the tissue gap between anvil member 16 and SULU 18.

Referring to FIGS. 1, 2 and 4, cartridge receiving half-section 14 includes a handle portion 22 and an integrally formed elongated channel portion 24 extending distally from handle portion 22. Handle portion 22 is ergonomically formed and includes a gripping portion 190 and a thumb engaging abutment 192. Handle portion 22 is perforated for ease of cleaning and/or to reduce the weight of surgical stapler 10. As will be discussed in further detail below, handle portion 22 defines a substantially U-shaped channel 22 a (FIG. 2) dimensioned to releasably receive firing assembly 20 and elongated channel portion 24 defines a substantially U-shaped channel 24 a dimensioned to releasably receive a SULU 18.

With reference still to FIGS. 1, 2 and 4, cartridge receiving half-section 14 further includes lateral support members 174 a, 174 b located proximal of elongated channel portion 24 and positioned to be received within semi-arcuate slots 172 a, 172 b, respectively, of clamping half-section 12. During assembly of clamping half-section 12 and cartridge receiving half-section 14, semi-arcuate slots 172 a, 172 b formed in anvil attachment portion 12 b of clamping half section 12 receive lateral support members 174 a, 174 b, respectively, of cartridge receiving half-section 14. The proximal end of cartridge receiving half-section 14 includes a vertical support member 188. Support member 188 includes a slot 188 a configured to selectively receive protrusion 186 formed on the proximal end of clamping half-section 12 when clamping half-section 12 is supported on cartridge receiving half-section 14 during assembly. Vertical slot 188 a is configured such that protrusion 186 of clamping half-section 12 snap-fits within vertical slot 188 a during assembly of staple 10 to secure clamping half-section 12 with cartridge receiving half-section 14. In one embodiment, vertical slot 188 a may be configured to receive protrusion 186 in a snap-fit type engagement.

With reference now to FIGS. 6-11B, firing assembly 20 includes a stationary housing 26 having a proximal end including detents 29. Detents 29 extend into recesses (not shown) formed in a proximal portion of handle portion 22 of cartridge receiving half-section 14 to releasably secure the proximal end of firing assembly 20 within substantially U-shaped channel 22 a of handle portion 22 as will be discussed in further detail below. The distal end of firing assembly 20 defines a triangular cutout 64 d which is positioned to receive a protrusion (not shown) formed on an inner wall of cartridge receiving half-section 14 to releasably secure the distal end of firing assembly 20 within handle portion 22. The structure of firing assembly 20 will also be discussed in further detail below. Likewise, SULU 18 includes a pair of distal protrusions 32 which are positioned in cutouts 34 (FIG. 4) formed at the distal end of channel portion 24 to releasably secure SULU 18 within channel portion 22. During assembly, firing assembly 20 must be inserted into U-shaped channel 22 a of handle portion 22 before SULU 18 is inserted into U-shaped channel 24 a of channel portion 24, as will be discussed below. To position SULU 18 in channel portion 24, protrusions 32 on SULU 18 are positioned within cutouts 34 while SULU 18 is positioned above and at an angle to channel portion 24. Thereafter, SULU 18 may be rotated downwardly into U-shaped channel 24 a. This allows for the drive components of firing assembly 20 to properly align with components of SULU 18 and also facilitates engagement of the firing assembly 20 with a knife 40 (FIG. 16) supported within SULU 18. A proximal end of SULU 18 includes an outwardly extending serrated surface 42 (FIG. 6) to facilitate gripping of the proximal end of SULU 18 to allow for removal and/or replacement of SULU 18 from channel portion 24. Prior to movement of stapler 10 to the clamped position, as will be discussed below, serrated gripping surface 42 will not fully seat within channel portion 24.

Referring to FIGS. 7-11B, firing assembly 20 also includes, a knife actuating bar 44, a cam bar 46, a guide block 48, a firing lever 50, a slide block 52 and a pedal 54. In one embodiment, stationary housing 26 includes a U-shaped frame 60 including a bottom wall 62 and a pair of sidewalls 64. The distal end of each sidewall 64 defines a proximal step 64 b, a distal angled portion 64 c (FIG. 8) and the triangular cutout 64 d. As discussed above, triangular cutout 64 d is positioned to receive a protrusion formed on an inner wall of handle portion 22.

With reference still to FIGS. 7-11B, guide block 48 includes a body defining three longitudinal slots 70 a-c and a pair of outwardly extending protrusions 72 (FIG. 11). In one embodiment, each protrusion 72 is substantially cylindrical and includes a tapered portion 72 a (FIG. 8). Alternately, other protrusion configurations are envisioned. Protrusions 72 are dimensioned to be received in openings 74 (FIG. 11) formed in sidewalls 64 of stationary housing 26 to axially fix guide block 48 within the distal end of stationary housing 26. Protrusions 72 allow for a degree of pivotal movement of guide block 48 within U-shaped frame 60. As will be discussed in further detail below, guide block 48 is pivotal from a first position in locking engagement with notches 49 and 51 of knife actuating bar 44 to a second position disengaged from notches 49 and 51 of knife actuating bar 44 in response to movement of stapler 10 to the clamped position. A torsion spring (not shown) is provided about protrusion 72 to urge guide block 48 into locking engagement with notches 49 and 51. Each of slots 70 a and 70 c is dimensioned to slidably receive a respective sidewall 114 of cam bar 46. Similarly, slot 70 b is dimensioned to slidably receive knife actuating bar 44.

Slide block 52 includes a hub 80 which includes a resilient finger 80 a configured to be snap-fit into a pivot hole 82 formed in firing lever 50. Firing lever 50 is pivotal about hub 80 when the slide block 52 is in a retracted position to facilitate actuation of the firing assembly 20 from either side of stapler 10. Pedal 54 (FIG. 11) is reciprocally received within a hole 84 formed in slide block 52. Pedal 54 includes a split body portion 54 a which is configured to straddle a proximal end 102 of knife actuating bar 44. In one embodiment, split body portion 54 a includes an angled distal surface 86. A pin 88 extends upwardly from pedal 54 through hole 84 in slide block 52. A biasing member 90 is positioned between split body portion 54 a and slide block 52, about pin 88 to urge pedal 54 downwardly away from slide block 52 to an extended position. In the retracted position of slide block 52, pedal 54 is received in a cutout (not shown) formed in a bottom wall of handle portion 22 of cartridge receiving half-section 14.

Firing lever 50 includes first and second finger engagement members 50 a and 50 b, either one of which can be selectively engaged to move the firing lever 50 through a firing stroke from either side of stapler 10. An arcuate recess 94 (FIG. 11B) is formed in a bottom surface of firing lever 50 which slidably receives pin 88 of pedal 54 to define the range of rotation through which firing lever 50 may pivot about hub 80 of slide block 52. As used herein, a firing stroke is defined as movement of firing lever 50 from a fully retracted position to a fully advanced position. A stop recess 94 a is formed at each end of arcuate recess 94. Stop recesses 94 a are configured and dimensioned to receive the end of pin 88 of pedal 54 to prevent pivotal movement of firing lever 50 about hub 80 during a firing stroke of surgical stapler 10. More specifically, when the firing assembly 20 is actuated to advance slide block 52 distally within stationary housing 26, angled distal surface 86 of pedal 54 engages handle portion 22 of cartridge receiving half-section 14 and is cammed out of a slot 121 (FIG. 11A) of stationary housing and a cutout (not shown) of channel 22 a to urge pin 88 upwardly into a stop recess 94 a to prevent pivotal movement of firing lever 50 during movement of firing lever 50 through a firing stroke. As is evident, pin 88 must be positioned beneath a stop recess 94 a to allow pedal 54 to lift upwardly from the cutout and slot 121 to allow firing lever 50 to be moved through the firing stroke. Thus, firing lever 50 must be pivoted to one side or the other of firing assembly 20 before the firing lever 50 can be moved through a firing stroke.

As shown in FIG. 11, knife actuating bar 44 includes a proximal end having a stepped portion 100 which includes a proximal first step 102 having a first height and a second step 104 having a second height which is greater than the first height. A distal end of actuating bar 44 includes an upturned hook portion 106 and upper and lower notches 49 and 51. A finger 108 projects upwardly from knife actuating bar 44 between first and second steps 102 and 104. Finger 108 is slidably received within a recess (not shown) formed in an underside of slide block 52. When slide block 52 is advanced distally within stationary housing 26, finger 108 moves within the recess such that slide block 52 moves in relation to knife actuating bar 44 until finger 108 engages a wall (not shown) defining a proximal end of the recess. When finger 108 engages the wall, further distal movement of slide block 52 will also effect distal movement of knife actuating bar 44. As will be evident below, this arrangement allows for staples to be ejected from SULU 18 prior to cutting of tissue by knife 40 (FIG. 16).

Referring to FIGS. 11 and 11A, cam bar 46 includes a pair of sidewalls 114 and a base wall 116 (FIG. 11A). The proximal end 114 a of each sidewall 114 includes a raised wall portion 118. Each raised wall portion 118 is configured to be fixedly received in a slot (not shown) formed in an underside of slide block 52 to fixedly secure the proximal end of cam bar 46 to slide block 52. Alternately, slide block 52 may be molded about the proximal end of knife actuating bar 44. The distal end of each sidewall 114 includes an angled camming surface 114 b. Base wall 116 defines a distally extending elongated slot 123 (FIG. 11A) which extends from the distal end of cam bar 46 along a substantial length of the cam bar 46 and a proximally extending longitudinal slot 121. Slot 121 is positioned to facilitate the passage of pedal 54 through the cutout (not shown) formed in the proximal end of channel 22 a of handle portion 22 when slide block 52 is in the retracted position.

Sidewalls 114 of cam bar 46 are slidably positioned in slots 70 a and 70 c of guide block 48 and knife actuating bar 44 is slidably positioned in longitudinal slot 70 b of guide block 48. When firing assembly 20 is supported in handle portion 22 of cartridge receiving half-section 14 and firing lever 50 is pivoted to one side of stationary housing 26 and pushed distally, slide block 52 is moved distally within stationary housing 26. As slide block 52 begins to move distally, tapered surface 86 of pedal 54 engages a proximal edge of handle portion 22 defining the cutout to urge pedal 54 upwardly out of the cutout, through slot 121 of cam bar 46, and onto an inner surface of stationary housing 26 of firing assembly 20. As this occurs, pin 88 of pedal 54 moves into a stop recess 94 a to prevent further pivotal movement of firing lever 50. If firing lever 50 is not pivoted to a position in which pin 88 is positioned beneath a stop recess 94 a, pedal 54 will be prevented from moving upwardly out of slot 121 and firing lever 50 will be prevented from moving through a firing stroke. As firing lever 50 is moved distally, finger 108 moves within the recess such that knife actuating bar 44 remains stationary as cam bar 46 is advanced distally. When finger 108 engages the proximal wall defining the recess formed in the underside of slide block 52, knife actuating bar 44 is moved distally with slide block 52 and cam bar 46. As will be discussed below, when cam bar 46 and knife actuating bar 44 are moved distally within stationary housing 26 of firing assembly 20 and handle portion 22, angled camming surfaces 114 b of cam bar 46 are moved through SULU 18 to eject fasteners from SULU 18. Simultaneously, although with a preset delay equal to the length of the recess formed in the underside of slide block 52, knife actuating bar 44 drives a knife blade 40 through SULU 18 to dissect tissue.

U.S. Pat. No. 7,631,794 (“the '794 patent”) discloses a surgical fastener applying apparatus which includes a firing assembly similar to that described above. The '794 patent is incorporated herein by reference in its entirety.

FIGS. 12-16 illustrate SULU 18. Referring to FIG. 16, SULU 18 includes a body 120, a plurality of staple pushers 122 (only one is shown), a bottom cover 124, a knife 40 having an angled sharpened leading edge or blade 40 a, a plurality of staples 126 (only one is shown), and a pivotally mounted safety lockout 128. A proximal end of body 120 includes a flexible finger 120 a which projects slightly beyond the outer wall defining body 120. Finger 120 a frictionally engages an inner wall of channel portion 24 to retain the proximal end of SULU 18 within channel portion 24 when SULU 18 is releasably positioned within channel portion 24. As is known in the art, body 120 has a plurality of rows of staple retaining slots 130, e.g., four, six, etc. and a linear slotted knife track 132 centrally disposed in body 120. Surgical stapler 10 can be dimensioned to receive or accommodate SULU's of different staple line lengths including, e.g., 60 mm, 80 mm and 100 mm. Knife 40 includes a downturned hook portion 40 b which is positioned to engage upturned hook portion 106 (FIG. 11) of knife actuating bar 44 when SULU 18 is positioned within channel portion 24.

In the illustrated embodiment, body 120 includes two staggered rows of slots 130 formed on either side of linear slotted knife track 132. The staggered rows of slots 130 extend beyond the distal end of knife track 132 to facilitate staple formation beyond the distal end of the stroke of the knife blade 40.

With reference still to FIGS. 12-16, staple pushers 122 may be configured to extend into one or more slots 130. In one embodiment, a single pusher is associated with each slot 130. Alternately, as illustrated in FIG. 16, each pusher 122 can be configured to extend into two adjacent slots 130 and is positioned beneath respective staples 126 which are retained in slots 130. As is known in the art, each pusher 122 includes a lower cam surface 122 a which is positioned to engage one of cam surfaces 114 b (FIG. 11) on the distal end of cam bar 46 such that movement of cam bar 46 through SULU 18 sequentially lifts each respective pusher 122 within its respective slot or slots 130 to eject staples from slots 130.

Bottom cover 124 partially encloses a channel (not shown) formed within the cartridge body 120. A longitudinal ridge 134 is formed on an upper surface of bottom cover 124 and provides a bearing surface for a knife supporting member 136 which is secured to a bottom edge of knife 40. Knife 40 may be secured to supporting member 136 via pins, welding or other known fastening techniques. During a firing stroke, knife 40 is guided along knife track 132 (FIG. 12) as the firing lever 50 is advanced through handle portion 22. A pair of slots 138 are defined between the sides of ridge 134 and an outer wall of cartridge body 120. Longitudinal ridge 134 is positioned within body 120 and dimensioned to be slidably received in elongated slot 120 (FIG. 12A) of cam bar 46 such that cam bar 46 is slidably movable through cartridge body 120 about longitudinal ridge 134 to eject staples 126 from SULU 18.

Safety lockout 128 is pivotally disposed on an upper proximal end of body 120 and is pivotal about a pivot member 150 from a locked orientation to unlocked orientation. Pivot member 150 is received in openings 154 in body 120. A biasing member, e.g., spring 152, is positioned between knife supporting member 136 and safety lockout 128 to urge safety lockout 128 towards the unlocked orientation. Safety lockout 128 includes a proximal hook 156 which is positioned to receive an engagement member 158 formed on the knife 40 to retain the safety lockout 128 in the locked orientation when the knife 40 is in the retracted position. When the knife 40 is moved towards the advanced position during a firing stroke, engagement member 158 is moved away from proximal hook 156 to allow safety lockout 128 to pivot towards the unlocked position in response to the urging of spring 152. It is noted that safety lockout 128 is prevented from pivoting to the unlocked position when clamping half-section 12 and cartridge receiving half-section 14 are in the clamped position because the top surface 128 a of safety lockout 128 engages an inner surface of clamping half-section 12 to prevent pivoting of safety lockout 128. Safety lockout 128 defines a slot 160 dimensioned to slidably receive the knife 40. In the retracted position of the knife 40, the leading edge 40 a of knife 40 is confined within slot 160 of safety lockout 128 to prevent accidental engagement and injury to medical personnel with leading edge 40 a of knife 40.

In order to load firing assembly 20 into handle portion 22 of cartridge receiving half-section 14, the stationary housing 26 of firing assembly 20 is slid into U-shaped channel of handle portion 22 through the proximal end of handle portion 22 until pivot members 29 are received in recesses 30 formed in the proximal end of handle portion 22. After firing assembly 20 is loaded, the SULU 18 may be loaded into U-shaped channel 24 a of channel portion 24 in the manner discussed above.

Referring to FIGS. 1-3, after SULU 18 and firing assembly 20 are loaded into cartridge receiving half-section 14, clamping half-section 12 may be assembled to cartridge receiving half-section 14. To attach clamping half-section 12 to cartridge receiving half-section 14, clamping half-section 12 is positioned such that lateral supports 174 a of cartridge receiving half-section 14 are received within first pair of semi-arcuate slots 172 a of anvil attachment portion 12 b and lateral supports 194 b are aligned with semi-arcuate slots 172 b. Thereafter, clamping half-section 12 is rotated towards cartridge receiving half-section 14 to position lateral supports members 172 b within semi-arcuate slots 194 b. Clamping half-section 12 is rotated until protrusion 186 formed on the proximal end of clamping half-section 12 is received within vertical slot 188 a formed in support 188 on the proximal end of cartridge receiving half-section 14. In the clamped position shown in FIG. 1, the staple deforming portion 198 of anvil member 16 is positioned in close approximation with the top surface of SULU 18.

Referring to FIGS. 7 and 11, as discussed above, guide block 48 is pivotally supported in stationary housing 26 of firing assembly 20. Guide block 48 includes a distally extending nose portion 220 (FIG. 11) which rests beneath SULU 18 when SULU 18 is supported in channel portion 24. The internal surface of guide block 48 includes locking surfaces (not shown) which are received in notches 49 and 51 of knife actuating bar 44 when the stapler 10 is in an unclamped position. When the SULU 18 is positioned in the channel portion 24, SULU 18 is positioned atop nose portion 220 and is not fully seated in the channel portion 24, as discussed above. When the stapler 10 is moved to the clamped position, locating fingers 170 (FIG. 2) of anvil member 160 engage a top surface of body 120 of SULU 18 to fully seat SULU 18 in channel portion 24. As discussed above, locating fingers 170 are received in grooves in SULU 18 to properly position SULU 18 in relation to anvil member 16. As SULU 18 is fully seated in channel portion 24, SULU 18 presses downwardly on nose portion 220 of guide block 48 to pivot guide block 48 about protrusions 72. When guide block 48 pivots, the locking surfaces move from notches 49 and 51 to unlock knife actuating bar 44. This configuration prevents movement of the knife actuating bar 44 in relation to guide block 48 prior to clamping to ensure that the knife actuating bar 44 and SULU knife 40 remain properly positioned for operational engagement prior to use.

When stapler 10 is in the clamped, unfired position, slide block 52 of firing assembly 20 is in the retracted position at the proximal end of handle portion 22 and stationary housing 26. In this position, pedal 54 is positioned in the cutout of channel 22 a and slot 121 of stationary housing 26 and pin 88 of pedal 54 is positioned in arcuate recess 94 of firing lever 50 beneath stop recesses 94 a. As such, firing lever 50 can be pivoted to facilitate actuation of surgical stapler 10 from either side of the stapler 10. In addition, in this position of slide block 52, finger 108 of knife actuating bar 44 is positioned adjacent the distal wall of the recess formed in the underside of slide block 52.

When slide block 52 is in the refracted position, knife 40 and cam surfaces 114 b of cam bar 46 are positioned in the proximal end of SULU 18 and, proximal hook 156 of safety lockout 128 is positioned in engagement with engagement member 158 of knife 40 to retain safety lockout 128 in the locked orientation. In addition, downturned hook portion 40 b of knife 40 is engaged with upturned hook portion 106 of knife actuating bar 44 to connect firing assembly 20 to knife 40 of SULU 18.

When the firing lever 50 is advanced distally, slide block 52 is moved distally within stationary housing 26 of firing assembly 20 to effect corresponding movement of cam bar 46 and delayed movement of knife actuating bar 44. As discussed above, the delayed movement of the knife actuating bar 44 is equal to the length of the recess formed in the underside of slide block 52 and results from movement of finger 108 of knife actuating bar 44 within the recess of slide block 52. Movement of knife actuating bar 44 with slide block 52 begins when finger 108 abuts the proximal wall of the recess formed in the underside of slide block 52. As cam bar 46 is moved distally through stationary housing 26 of firing assembly 20, cam surfaces 114 b on sidewalls 114 of cam bar 46 are advanced through SULU 18 to sequentially engage pushers 122 to eject staples 126 from slots 130 of body 120. Concurrently, since the distal end of knife actuating bar 44 is engaged with knife 40, knife 40, after the preset delay, is advanced through SULU 18 to incise tissue between the staple lines.

When slide block 52 moves distally within stationary housing 26, pedal 54 rides up over handle portion 22 and moves along inner surface of stationary housing 26 of firing assembly 20. When this occurs, pin 88 of pedal 54 moves into a stop recess 94 a to prevent further pivotal movement of firing lever 50.

When knife 40 is moved distally within SULU 18, engagement member 158 of knife 40 is disengaged with proximal hook 156 of safety lockout 128.

Firing lever 50 is returned to its proximal-most position to retract cam bar 46 and knife 40. Surgical stapler 10 is moved to an open position by disengaging protrusion 186 formed on the proximal end of clamping half-section 12 from within vertical slot 188 a formed in support member 188 on the proximal end of cartridge receiving half-section 14. In the open position, clamping half-section 12 is spaced from cartridge receiving half-section 14 and spring 152 (FIG. 16) pivots safety lockout 128 about pivot member 150 to its unlocked position such that safety lockout 128 projects upwardly from SULU 18. In the unlocked position, safety lockout 128 prevents movement of the stapler 10 back to the clamped position. In order to reuse surgical stapler 10, used SULU 18 must be replaced with a new SULU 18.

During a surgical procedure, SULU 18 may be replaced multiple times to facilitate multiple uses of stapler 10 on a single patient. Since each SULU 18 is provided with a fresh knife 40, tearing of tissue is minimized. After the surgical procedure, the used SULU(S) 18 and the firing assembly 20 may be removed from cartridge receiving half-section 14 and disposed of in an appropriate manner. Clamping half-section 12, cartridge receiving half-section 14 and anvil member 16 may now be sterilized, such as by autoclaving, and reused with a sterilized SULU 18 and firing assembly 20 in the manner discussed above. Because the firing assembly 20 is disposable, fewer areas remain on the reusable components for tissue and fluids to become trapped. As such, the reusable components of the apparatus may be more easily sterilized. As noted above, in an alternative embodiment, anvil member 16 may also be disposed of after a surgical procedure.

It will be understood that various modifications may be made to the embodiments of the surgical fastener applying apparatus disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. 

What is claimed is:
 1. A surgical fastener applying apparatus comprising: a clamping half-section including a distal anvil attachment portion and a proximal handle portion; a cartridge receiving half-section including a handle portion and an elongated channel portion, the elongated channel portion being configured to releasably receive a single use loading unit and the handle portion being configured to releasably receive a firing assembly, an anvil member including an anvil attachment section and a staple deforming section positioned distally of the anvil attachment section, the anvil attachment section being configured to be releasably coupled to the distal anvil attachment portion of the clamping half-section to allow for separation of the anvil member from the clamping half-section after each use of the surgical fastener applying apparatus to facilitate sterilization; and a firing assembly configured to be releasably supported within the handle portion of the cartridge receiving half-section.
 2. The surgical fastener applying apparatus according to claim 1, wherein the firing assembly includes a stationary housing, a firing lever, and a cam bar secured to the firing lever.
 3. The surgical fastener applying apparatus according to claim 1, wherein the anvil member is disposable independently of the clamping half-section and the clamping half-section is reusable.
 4. The surgical fastener applying apparatus according to claim 2, wherein the stationary housing includes a U-shaped frame having a bottom wall and a pair of sidewalls.
 5. The surgical fastener applying apparatus according to claim 4, wherein each of the sidewalls have a proximal end defining detents which are configured to extend through openings in a proximal end of the cartridge receiving half-section to releasably retain the stationary housing within the handle portion of the cartridge receiving half-section.
 6. The surgical fastener applying apparatus according to claim 2, wherein the firing assembly further includes a knife actuating bar which is configured to engage a knife supported within the single use loading unit.
 7. The surgical fastener applying apparatus according to claim 4, wherein the firing assembly further includes a guide block axially fixed within the U-shaped frame and a slide block slidably positioned with the U-shaped frame, wherein the firing lever is pivotally secured to the slide block and the cam bar is fixedly secured to the slide block, the slide block being slidable through the U-shaped frame to advance the cam bar through a distal portion of the elongated channel portion.
 8. The surgical fastener applying apparatus according to claim 1, wherein the cartridge receiving half-section includes a support member on a proximal end thereof defining a vertical slot and the clamping half-section includes a protrusion on a proximal end thereof configured to releasably engage the support member.
 9. The surgical fastener applying apparatus according to claim 1, wherein the distal anvil attachment portion includes a pair of longitudinally spaced cylindrical posts configured to releasably engage a proximal portion of the anvil member.
 10. The surgical fastener applying apparatus according to claim 9, wherein the anvil member includes a pair of slots.
 11. The surgical fastener applying apparatus according to claim 10, wherein the pair of slots are configured to receive the pair of cylindrical posts.
 12. The surgical fastener applying apparatus according to claim 10, wherein the pair of slots have open ends which face in different directions.
 13. The surgical fastener applying apparatus according to claim 1, wherein the distal anvil attachment portion includes two pairs of semi-arcuate slots each configured to selectively receive a pair of lateral support members formed on the cartridge receiving half-section.
 14. The surgical fastener applying apparatus according to claim 1, wherein the handle portion of each of the clamping half-section and the cartridge receiving half-section is perforated.
 15. The surgical fastener applying apparatus according to claim 1, wherein the handle portion of each of the clamping half-section and the cartridge receiving half-section includes a gripping portion.
 16. The surgical fastener applying apparatus according to claim 1, wherein the handle portion of each of the clamping half-section and the cartridge receiving half-section includes a thumb engaging abutment.
 17. The surgical fastener applying apparatus according to claim 1, further including a single use loading unit configured to be releasably received within the elongated channel portion of the cartridge receiving half-section. 